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<div class="title">qwt_math.h</div>  </div>
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<div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="comment">/* -*- mode: C++ ; c-file-style: &quot;stroustrup&quot; -*- *****************************</span></div>
<div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="comment"> * Qwt Widget Library</span></div>
<div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="comment"> * Copyright (C) 1997   Josef Wilgen</span></div>
<div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment"> * Copyright (C) 2002   Uwe Rathmann</span></div>
<div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment"> *</span></div>
<div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment"> * This library is free software; you can redistribute it and/or</span></div>
<div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment"> * modify it under the terms of the Qwt License, Version 1.0</span></div>
<div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="comment"> *****************************************************************************/</span></div>
<div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160; </div>
<div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="preprocessor">#ifndef QWT_MATH_H</span></div>
<div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="preprocessor">#define QWT_MATH_H</span></div>
<div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160; </div>
<div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="preprocessor">#include &quot;qwt_global.h&quot;</span></div>
<div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160; </div>
<div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="preprocessor">#if defined(_MSC_VER)</span></div>
<div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160;<span class="comment">/*</span></div>
<div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="comment">  Microsoft says:</span></div>
<div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="comment"></span> </div>
<div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="comment">  Define _USE_MATH_DEFINES before including math.h to expose these macro</span></div>
<div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;<span class="comment">  definitions for common math constants.  These are placed under an #ifdef</span></div>
<div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;<span class="comment">  since these commonly-defined names are not part of the C/C++ standards.</span></div>
<div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;<span class="comment">*/</span></div>
<div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;<span class="preprocessor">#define _USE_MATH_DEFINES 1</span></div>
<div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160; </div>
<div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;<span class="preprocessor">#include &lt;qmath.h&gt;</span></div>
<div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;<span class="preprocessor">#include &quot;qwt_global.h&quot;</span></div>
<div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160; </div>
<div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;<span class="preprocessor">#ifndef M_PI_2</span></div>
<div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;<span class="comment">// For Qt &lt;= 4.8.4 M_PI_2 is not known by MinGW-w64</span></div>
<div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;<span class="comment">// when compiling with -std=c++11</span></div>
<div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;<span class="preprocessor">#define M_PI_2 (1.57079632679489661923)</span></div>
<div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160; </div>
<div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;<span class="preprocessor">#ifndef LOG_MIN</span></div>
<div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;<span class="preprocessor">#define LOG_MIN 1.0e-100</span></div>
<div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160; </div>
<div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;<span class="preprocessor">#ifndef LOG_MAX</span></div>
<div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;<span class="preprocessor">#define LOG_MAX 1.0e100</span></div>
<div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;<span class="preprocessor">#endif</span></div>
<div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160; </div>
<div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160;QWT_EXPORT <span class="keywordtype">double</span> qwtGetMin( <span class="keyword">const</span> <span class="keywordtype">double</span> *array, <span class="keywordtype">int</span> size );</div>
<div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;QWT_EXPORT <span class="keywordtype">double</span> qwtGetMax( <span class="keyword">const</span> <span class="keywordtype">double</span> *array, <span class="keywordtype">int</span> size );</div>
<div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160; </div>
<div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;QWT_EXPORT <span class="keywordtype">double</span> qwtNormalizeRadians( <span class="keywordtype">double</span> radians );</div>
<div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;QWT_EXPORT <span class="keywordtype">double</span> qwtNormalizeDegrees( <span class="keywordtype">double</span> degrees );</div>
<div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160; </div>
<div class="line"><a name="l00063"></a><span class="lineno">   63</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">int</span> qwtFuzzyCompare( <span class="keywordtype">double</span> value1, <span class="keywordtype">double</span> value2, <span class="keywordtype">double</span> intervalSize )</div>
<div class="line"><a name="l00064"></a><span class="lineno">   64</span>&#160;{</div>
<div class="line"><a name="l00065"></a><span class="lineno">   65</span>&#160;    <span class="keyword">const</span> <span class="keywordtype">double</span> eps = qAbs( 1.0e-6 * intervalSize );</div>
<div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160; </div>
<div class="line"><a name="l00067"></a><span class="lineno">   67</span>&#160;    <span class="keywordflow">if</span> ( value2 - value1 &gt; eps )</div>
<div class="line"><a name="l00068"></a><span class="lineno">   68</span>&#160;        <span class="keywordflow">return</span> -1;</div>
<div class="line"><a name="l00069"></a><span class="lineno">   69</span>&#160; </div>
<div class="line"><a name="l00070"></a><span class="lineno">   70</span>&#160;    <span class="keywordflow">if</span> ( value1 - value2 &gt; eps )</div>
<div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;        <span class="keywordflow">return</span> 1;</div>
<div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160; </div>
<div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;    <span class="keywordflow">return</span> 0;</div>
<div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;}</div>
<div class="line"><a name="l00075"></a><span class="lineno">   75</span>&#160; </div>
<div class="line"><a name="l00076"></a><span class="lineno">   76</span>&#160; </div>
<div class="line"><a name="l00077"></a><span class="lineno">   77</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">bool</span> qwtFuzzyGreaterOrEqual( <span class="keywordtype">double</span> d1, <span class="keywordtype">double</span> d2 )</div>
<div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;{</div>
<div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;    <span class="keywordflow">return</span> ( d1 &gt;= d2 ) || qFuzzyCompare( d1, d2 );</div>
<div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;}</div>
<div class="line"><a name="l00081"></a><span class="lineno">   81</span>&#160; </div>
<div class="line"><a name="l00082"></a><span class="lineno">   82</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">bool</span> qwtFuzzyLessOrEqual( <span class="keywordtype">double</span> d1, <span class="keywordtype">double</span> d2 )</div>
<div class="line"><a name="l00083"></a><span class="lineno">   83</span>&#160;{</div>
<div class="line"><a name="l00084"></a><span class="lineno">   84</span>&#160;    <span class="keywordflow">return</span> ( d1 &lt;= d2 ) || qFuzzyCompare( d1, d2 );</div>
<div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160;}</div>
<div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160; </div>
<div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">int</span> qwtSign( <span class="keywordtype">double</span> x )</div>
<div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;{</div>
<div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;    <span class="keywordflow">if</span> ( x &gt; 0.0 )</div>
<div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;        <span class="keywordflow">return</span> 1;</div>
<div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;    <span class="keywordflow">else</span> <span class="keywordflow">if</span> ( x &lt; 0.0 )</div>
<div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;        <span class="keywordflow">return</span> ( -1 );</div>
<div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;    <span class="keywordflow">else</span></div>
<div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;        <span class="keywordflow">return</span> 0;</div>
<div class="line"><a name="l00096"></a><span class="lineno">   96</span>&#160;}</div>
<div class="line"><a name="l00097"></a><span class="lineno">   97</span>&#160; </div>
<div class="line"><a name="l00099"></a><span class="lineno">   99</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">double</span> qwtSqr( <span class="keywordtype">double</span> x )</div>
<div class="line"><a name="l00100"></a><span class="lineno">  100</span>&#160;{</div>
<div class="line"><a name="l00101"></a><span class="lineno">  101</span>&#160;    <span class="keywordflow">return</span> x * x;</div>
<div class="line"><a name="l00102"></a><span class="lineno">  102</span>&#160;}</div>
<div class="line"><a name="l00103"></a><span class="lineno">  103</span>&#160; </div>
<div class="line"><a name="l00105"></a><span class="lineno">  105</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">double</span> qwtFastAtan( <span class="keywordtype">double</span> x )</div>
<div class="line"><a name="l00106"></a><span class="lineno">  106</span>&#160;{</div>
<div class="line"><a name="l00107"></a><span class="lineno">  107</span>&#160;    <span class="keywordflow">if</span> ( x &lt; -1.0 )</div>
<div class="line"><a name="l00108"></a><span class="lineno">  108</span>&#160;        <span class="keywordflow">return</span> -M_PI_2 - x / ( x * x + 0.28 );</div>
<div class="line"><a name="l00109"></a><span class="lineno">  109</span>&#160; </div>
<div class="line"><a name="l00110"></a><span class="lineno">  110</span>&#160;    <span class="keywordflow">if</span> ( x &gt; 1.0 )</div>
<div class="line"><a name="l00111"></a><span class="lineno">  111</span>&#160;        <span class="keywordflow">return</span> M_PI_2 - x / ( x * x + 0.28 );</div>
<div class="line"><a name="l00112"></a><span class="lineno">  112</span>&#160; </div>
<div class="line"><a name="l00113"></a><span class="lineno">  113</span>&#160;    <span class="keywordflow">return</span> x / ( 1.0 + x * x * 0.28 );</div>
<div class="line"><a name="l00114"></a><span class="lineno">  114</span>&#160;}</div>
<div class="line"><a name="l00115"></a><span class="lineno">  115</span>&#160; </div>
<div class="line"><a name="l00117"></a><span class="lineno">  117</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">double</span> qwtFastAtan2( <span class="keywordtype">double</span> y, <span class="keywordtype">double</span> x )</div>
<div class="line"><a name="l00118"></a><span class="lineno">  118</span>&#160;{</div>
<div class="line"><a name="l00119"></a><span class="lineno">  119</span>&#160;    <span class="keywordflow">if</span> ( x &gt; 0 )</div>
<div class="line"><a name="l00120"></a><span class="lineno">  120</span>&#160;        <span class="keywordflow">return</span> qwtFastAtan( y / x );</div>
<div class="line"><a name="l00121"></a><span class="lineno">  121</span>&#160; </div>
<div class="line"><a name="l00122"></a><span class="lineno">  122</span>&#160;    <span class="keywordflow">if</span> ( x &lt; 0 )</div>
<div class="line"><a name="l00123"></a><span class="lineno">  123</span>&#160;    {</div>
<div class="line"><a name="l00124"></a><span class="lineno">  124</span>&#160;        <span class="keyword">const</span> <span class="keywordtype">double</span> d = qwtFastAtan( y / x );</div>
<div class="line"><a name="l00125"></a><span class="lineno">  125</span>&#160;        <span class="keywordflow">return</span> ( y &gt;= 0 ) ? d + M_PI : d - M_PI;</div>
<div class="line"><a name="l00126"></a><span class="lineno">  126</span>&#160;    }</div>
<div class="line"><a name="l00127"></a><span class="lineno">  127</span>&#160; </div>
<div class="line"><a name="l00128"></a><span class="lineno">  128</span>&#160;    <span class="keywordflow">if</span> ( y &lt; 0.0 )</div>
<div class="line"><a name="l00129"></a><span class="lineno">  129</span>&#160;        <span class="keywordflow">return</span> -M_PI_2;</div>
<div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160; </div>
<div class="line"><a name="l00131"></a><span class="lineno">  131</span>&#160;    <span class="keywordflow">if</span> ( y &gt; 0.0 )</div>
<div class="line"><a name="l00132"></a><span class="lineno">  132</span>&#160;        <span class="keywordflow">return</span> M_PI_2;</div>
<div class="line"><a name="l00133"></a><span class="lineno">  133</span>&#160; </div>
<div class="line"><a name="l00134"></a><span class="lineno">  134</span>&#160;    <span class="keywordflow">return</span> 0.0;</div>
<div class="line"><a name="l00135"></a><span class="lineno">  135</span>&#160;}</div>
<div class="line"><a name="l00136"></a><span class="lineno">  136</span>&#160; </div>
<div class="line"><a name="l00138"></a><span class="lineno">  138</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">double</span> qwtRadians( <span class="keywordtype">double</span> degrees )</div>
<div class="line"><a name="l00139"></a><span class="lineno">  139</span>&#160;{</div>
<div class="line"><a name="l00140"></a><span class="lineno">  140</span>&#160;    <span class="keywordflow">return</span> degrees * M_PI / 180.0;</div>
<div class="line"><a name="l00141"></a><span class="lineno">  141</span>&#160;}</div>
<div class="line"><a name="l00142"></a><span class="lineno">  142</span>&#160; </div>
<div class="line"><a name="l00144"></a><span class="lineno">  144</span>&#160;<span class="keyword">inline</span> <span class="keywordtype">double</span> qwtDegrees( <span class="keywordtype">double</span> degrees )</div>
<div class="line"><a name="l00145"></a><span class="lineno">  145</span>&#160;{</div>
<div class="line"><a name="l00146"></a><span class="lineno">  146</span>&#160;    <span class="keywordflow">return</span> degrees * 180.0 / M_PI;</div>
<div class="line"><a name="l00147"></a><span class="lineno">  147</span>&#160;}</div>
<div class="line"><a name="l00148"></a><span class="lineno">  148</span>&#160; </div>
<div class="line"><a name="l00149"></a><span class="lineno">  149</span>&#160;<span class="preprocessor">#endif</span></div>
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